Sinker arrangement for knitting machines



Dec. 7, 1965 s. MISHCON 3,221,521

SINKER ARRANGEMENT FOR KNITTING MACHINES Filed Oct. 18, 1962 un- 32 o 23 INVENTOR. & 3| 28 SAM MISHCON l4 BY l a ,fl- 2O m ATTORNEY United States Patent 3,221,521 SINKER ARRANGEMENT FOR KNlTTiNG MACHINES Sam Mishcon, Miami Beach, Fla, assignor, by mesne assignments, to The Singer Company, New York, N.Y.,

a corporation of New Jersey Filed Get. 18, 1962, Ser. No. 231,518 3 Claims. (Cl. 66-407) This invention relates to sinker top knitting machines, and more particularly, to knitting machines employing hold-down type sinkers.

It is an object of this invention to provide a novel and improved hold-down sinker arrangement in a knitting machine.

An object of this invention is to provide in latch needle sinker top circular knitting machines a novel platen ring atop the needle cylinder which platen ring is formed with a planar sinker blade engaging surface that will remain substantially lint free because of the absence of the conventional sinker guide slots therein.

Another object of this invention is to provide a knitting machine in which the body portions of the sinkers define the knitting line with greater uniformity than has been heretofore attainable.

It is also an object of this invention to provide a novel and effective means for steadying the needles substantially at the knitting line to prevent inward deflection thereof.

With the above and additional objects and advantages in view, as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawing of a preferred embodiment in which:

FIG. 1 represents a vertical, cross-sectional view through the cylinder top of a circular latch needle knitting machine having the sinker construction and arrangement of this invention applied thereto.

FIG. 2 is a perspective view of a modified form of sinker adapted for use with the arrangement illustrated in FIG. 1 and shown with a fragment of the sinker platen ring carried at the top of the cylinder.

FIG. 3 represents an enlarged vertical cross-sectional view through the cylinder top similar to that of FIG. 1 but illustrating a modified form of this invention and FIG. 4 is a perspective view of several sinkers of the type illustrated in FIG. 3 together with fragments of the sinker platen ring and of the needle stabilizing ring.

It is a primary function of hold-down sinkers to support the knitted fabric web from above as well as from below; and in particular, to support the last formed sinker loops of yarn i.e., those extending between the stitch loops which are being drawn down by the needles. Whereas on the rise of the needles, hold-down type sinkers serve to constrain the yarn loops on the needles and prevent them from rising with the needles, on the downstroke or draw of the needles, the sinkers in supporting the previously formed yarns in the fabric define a knitting line with reference to which the length of the stitches and thus the characteristic of the knit fabric is determined. For the production of high quality knit fabric, it is essential that the sinkers define a uniform and unvarying knitting line so that the stitches will be uniform throughout the fabric.

The individual sinkers may be manufactured to very close tolerances. However, it has been conventional in sinker top machines of the hold-down variety to provide a radially slotted sinker platen ring atop the needle cylinder with each sinker slidably bottomed in one of the radial slots therein. Such platen rings have proven exceedingly diflicult to manufacture to the tolerances necessary for the requisite uniformity of support for the 'ice sinkers, particularly because of the distortion of the sinker platen ring during the necessary annealing, slotting, hardening, and finishing operations thereon.

A further difiiculty experienced with the conventional machine construction including a radially slotted sinker platen ring is that even if manufactured to the requisite tolerances, the sinker guide slots collect lint during machine operation.

These machines are subject, therefore, to the interposition of foreign material between certain of the sinkers and the platen ring which contributes to uneven stitch formation, the necessity frequently to stop production on the machine to remove lint accumulation, and the possibility of staining the fabric in the lint clearing process.

The present invention comprehends the use of a flat slot-free sinker supporting surface atop the needle cylinder which may be ground to an exceedingly close tolerance without distortion, and which is free of lint accumulating depressions. With this construction, the machine may be operated for long periods without interruption for lint cleaning purposes.

Referring to the drawings, a hold-down sinker is indicated generally at 11. The sinker is formed with a body portion 12 having an under surface 13 which extends across the top of the needle cylinder 14, and a substantially parallel upper web supporting surface 15. A nose 16 projecting over the web-supporting surface 15 forms therewith a throat 17. A shank 18 extending from the body portion is formed with an upstanding butt 19.

The needle cylinder 14 formed with evenly spaced vertical needle slots 20 has secured at the top a sinker platen ring 21 formed with a flat planar sinker supporting surface 22 upon which the undersurfaces 13 of the sinkers bear. The sinker platen ring 21 is formed with a depending annular flange 23 adapted to locate the platen ring concentrically atop the needle cylinder. The fiat surface 22 upon which the undersurfaces 13 of the sinkers bear provides the sole guide surface on the needle cylinder for the sinkers.

The needle cylinder is supported for rotation relatively to a machine frame (not shown) and relatively to section blocks 24 which sustain various needle raising cams 25 and stitch cams 26 which operate upon needle butts 27 so as to reciprocate latch knitting needles 28 constrained one in each needle slot 20 in the cylinder.

Fixed to the machine frame adjacent to the rotating needle cylinder is a carrier ring 29 to which is secured a sinker cam ring 30. Journaled beneath the sinker cam ring 30 is a sinker rest ring 31 formed with upwardly open radial slots 32, each slot adapted to accommodate the shank 18 of one of the sinkers 11. The sinker rest ring 31 meshes with the needle slots 20 of the needle cylinder thus to lock the sinker rest ring 30 for rotation with the needle cylinder 14. The sinker butts are embraced between a cam shoulder 33 formed on the sinker cam ring 29 and sinker cam members 34- carried thereon so that as the sinkers are carried by the sinker rest ring, the sinker cams cause the sinkers to reciprocate radially relatively to the needle cylinder and the platen ring 21 With the construction of this invention, timed interrelated movements are imparted to the needles and sinkers in conventional fashion. When the needles are elevated, as illustrated in FIG. 1, the adjacent sinkers are shifted radially inwardly so as to constrain in the sinker throats 17 the yarn loops extending between the last formed stitches on the needles, thus facilitating latch clearance on those needles raised to the knit position.

On the down stroke of the needles, as illustrated in FIG. 3, the adjacent sinkers are shifted radially outwardly so that the yarn fed to the needles may be drawn onto the web supporting surfaces 15 of the sinkers.

The web supporting surface 15 of each sinker thus defines a line of reference with respect to which the draw of the adjacent needles determines the stitch length of the knitting in that area of the cloth. Collectively the web supporting surfaces of all the sinkers should define a reference plane if uniform unblemished fabric is to be knit on the machine. The construction of the sinker platen ring of this invention and the sinker arrangement therewith provides for a more initially accurate and uniformly planar support for the sinker web supporting surfaces. The arrangement of this invention is also far less conducive to collection of lint or foreign material which might change the web supporting surface eleva tion of certain sinkers which would streak or mar the knit fabric.

Nothing forming a part of or attached to the needle cylinder extends either above or on either side of, that is, radially inward or outward of the planar surface 22. The fiat planar sinker supporting surface 22, as illustrated in each of the figures of the drawing thus defines one extremity of the needle supporting member 14.

FIG. 2 illustrates the manner in which a sinker 11 cooperates with the platen ring 21. In FIG. 2, the sinker 11 has a form slightly modified over that illustrated in FIG. 1 in that the upper section of the body portion 12 encompassing the web supporting surface 15, the nose 16 and the throat 17 is formed substantially thinner than the shank 18 and lower section of the body portion 12. In this way, additional stiffness may be provided for the sinker without increasing the danger of cramping or pinching the yarns or the web between adjacent sinkers or between the sinkers and adjacent needles.

FIGS. 3 and 4 illustrate a further modified form of sinker construction and arrangement in which the sinker body portion 12 is formed with an aperture or slot 40 beneath the web supporting surface 15 with the side walls of the slot 40 being substantially parallel to the web supporting surface 15 and under surfaces 13 of the sinker. The slots 40 which are preferably open at the free extremity of the sinker body portions slidably constrain an annular needle backing ring 41 which may be formed with a downwardly flared inner periphery 42 over which the web of knit fabric passes. The outer peripheral portion of the needle backing ring 41 is preferably fiat and the outer periphery 43 made circular and of a dimension so as to fit snugly within the circular bank of needles, the ring 41 being maintained centered relatively to the cylinder 14 by the needles and particularly those of the needles occupying a raised position. The needle backing ring 41 provides support for the needles adjacent to the web supporting surface 15 of the sinkers and prevents deflection or tipping of the needles because of the tension on the web which might otherwise tend to shift the needle butts out of the needle slots in the cylinder or to carry the needle out of cooperative relation with the yarn feed.

Having set forth the nature of this invention, what is claimed herein is:

1. In a circular knitting machine having a needle cylinder formed peripherally with substantially parallel needle accommodating slots, a bank of knitting needles endwise slidably constrained one in each of said needle cylinder slots, a bank of endwise reciprocatory hold- 4 down type sinkers interdigitated with said needles, a platen ring secured atop said needle cylinder, said platen ring being formed with a substantially planar sinker supporting top surface defining the upper extremity of means carried by said needle cylinder and defining the sole guide surface on said needle cylinder for said sinkers, each sinker having a web supporting blade formed with an under surface of uniform thickness engaging said planar top surface of said platen ring, the web supporting blade of each sinker being provided with an upper portion of reduced thickness, said upper portion of reduced thickness being formed with a web supporting surface, and a web hold-down finger overlying said web supporting surface and defining therebetween a web accommodating slot.

2. In a circular knitting machine having a needle cylinder formed peripherally with substantially parallel needle accommodating slots, a bank of knitting needles endwise slidably constrained one in each of said needle cylinder slots, and a bank of endwise reciprocatory holddown type sinkers interdigitated with said needles, each sinker having a web supporting blade and an overlying web hold-down finger defining with said web supporting 1 blade, a web accommodating slot, a platen ring secured atop said needle cylinder, said platen ring being formed with a substantially planar sinker supporting top surface defining the upper extremity of means carried by said needle cylinder and defining the sole guide surface for said sinker web supporting blades on said needle cylinder, the web supporting blade of each of said sinkers being formed with an elongate aperture beneath and substantially parallel to said web accommodating slot, and an annular needle backing ring disposed within said bank of knitting needles and constrained solely in said elongate sinker apertures.

3. In a circular knitting machine having a needle cylinder formed peripherally with substantially parallel needle accommodating slots, a bank of knitting needles endwise slidably constrained one in each of said needle cylinder slots, and a bank of endwise reciprocatory holddown type sinkers interdigitated with said needles, each sinker having a web supporting blade and an overlying web hold-down finger defining with said web supporting blade, at web accommodating slot, a platen ring secured atop said needle cylinder, said platen ring being formed with a substantially planar sinker supporting top surface defining the upper extremity of means carried by said needle cylinder and defining the sole guide surface of said sinker web supporting blades on said needle cylinder, the web supporting blade of each of said sinkers being formed with an additional slot beneath and substantially parallel to said web accommodating slot and open at the free extremity of said sinker web supporting blade, and an annular needle backing ring having a flat outer peripheral portion constrained solely in said additional sinker slots and formed with a circular outer edge disposed within said bank of knitting needles, and having a flared web engaging inner periphery.

References Cited by the Examiner UNITED STATES PATENTS 561,038 5/1898 Williams 66115 2,596,535 5/1952 Curtis 66107 2,715,824 8/1955 Krauss et a1. 6693 2,945,368 7/1960 Fried 6 6115 RUSSELL C. MADER, Primary Examiner. 

1. IN A CIRCULAR KNITTING MACHINE HAVING A NEEDLE CYLINDER FORMED PERIPHERALLY WITH SUBSTANTIALLY PARALLEL NEEDLE ACCOMMODATING SLOTS, A BANK OF KNITTING NEEDLES ENDWISE SLIDABLY CONSTRAINED ONE IN EACH OF SAID NEEDLE CYLINDER SLOTS, A BANK OF ENDWISE RECIPROCATORY HOLDDOWN TYPE SINKERS INTERDIGITATED WITH SAID NEEDLES, A PLATEN RING SECURED ATOP SAID NEEDLE CYLINDER, SAID PLATEN RING BEING FORMED WITH A SUBSTANTIALLY PLANAR SINKER SUPPORTING TOP SURFACE DEFINING THE UPPER EXTERMITY OF MEANS CARRIED BY SAID NEEDLE CYLINDER AND DEFINING THE SOLE GUIDE SURFACE ON SAID NEEDLE CYLINDER FOR SAID SINKERS, EACH SINKER HAVING A WEB SUPPORTING BLADE FORMED WITH AN UNDER SURFACE OF UNIFORM THICKNESS ENGAGING 